#include<iostream>

int main()
{
	using namespace std;
	
	int hex_num = 0x1a;
	int dec_num = 12;
	int oct_num = 12;
	
	cout << "by dec:\n" << dec << hex_num << " " << dec_num << " " << oct_num << endl;
	cout << "by hex:\n" << hex << hex_num << " " << dec_num << " " << oct_num << endl;
	cout << "by oct:\n" << dec << hex_num << " " << dec_num << " " << oct_num << endl;
	
	return 0;
}
